Electroosmotic flow in polymer-coated slits: a joint experimental/simulation study

The quality of separation in capillaries electrophoresis is strongly affected by the magnitude of the electroosmotic flow (EOF). The EOF can be efficiently suppressed by coating the capillary wall with hydrophilic polymers. In this paper, experimental data are presented to show the effect of coating thickness and charge on mass transport. Simulations performed with the lattice Boltzmann technique quantitatively reproduce the EOF with and without the coating and with either a neutral or charged coating layer. Experimental, simulation and theoretical analyses converge toward the interpretation that EO suppression arises from the frictional forces acting on the ionic currents and that a detailed representation of the polymeric coating is not needed in order to capture the phenomenon.